Zia was commissioned in 1945 from the Royal Indian Military Academy in Dehra Dun and served with the British armoured forces in Southeast Asia at the end of World War II. After 19 years spent in various staff and command appointments he was made an instructor at the Command and Staff College in Quetta. He successively commanded a regiment, brigade, division, and a corps during the period 1966–72. A major general from 1972, he was president of the military courts that tried several Army and Air Force officers alleged to have plotted against the government of Prime Minister Zulfikar Ali Bhutto in 1972. Bhutto promoted him to lieutenant general in 1975 and made him chief of Army staff in 1976.

Zia seized power from Bhutto in a bloodless coup on July 5, 1977, and became chief martial-law administrator while retaining his position as Army chief of staff. He assumed the presidency after Fazal Elahi Chaudhry resigned. Zia tightened his hold on the government after having the charismatic and still-popular Bhutto executed on charges of attempted murder in 1979. Zia suspended political parties in that year, banned labour strikes, imposed strict censorship on the press, and declared martial law in the country (nominally lifted 1985). He responded to the Soviet Union’s invasion of neighbouring Afghanistan in 1979 by embarking on a U.S.-financed military buildup. He also tried to broaden his base of support and worked for the Islamization of Pakistan’s political and cultural life. He died in an airplane crash.